Argentina's president, Cristina Fernández de Kirchner, has announced that she will seek re-election, ending months of speculation about her political plans.

In a nationally televised address, she said: "We are going to go submit ourselves to the ballot boxes once again."

Kirchner, who succeeded her late husband, Nestor Kirchner, in the presidency, added: "I always knew what I had to do because I've always had a high sense of political responsibility and what must be done."

She is expected to have the upper hand in the October election as she has capitalised on a growing economy, the lack of a strong challenger and her image as a grieving widow.

Political analysts agree that given the political landscape in Argentina, Kirchner is by some distance the frontrunner and that barring a major political fiasco she could win in the first round of voting on 23 October.

"If nothing exceptional happens, I think she'll win in the first round. The opposition is very disoriented," said Sebastian Juncal, an analyst with the Buenos Aires-based Centre for Studies of the State and Society. As for the opposition, Juncal said: "Their chances are very low because they haven't been able to present a clear message and a platform that interests voters."

The latest poll by the private Centre of Public Opinion Studies found that if elections were held , Kirchner would receive about 47% of the vote, followed by 15% for opposition congressman Ricardo Alfonsín, the son of the former president Raul Alfonsín, and 7% for fellow Peronist former president Eduardo Duhalde.

If Kirchner wins, she would keep her Peronist party in power for an unprecedented 12 years, a husband-and-wife dynasty that began when Nestor Kirchner took office in 2003.

Kirchner's first-round election victory in October 2007 was widely attributed to the support of her popular husband, whom many Argentinians credited with reviving the country after its 2001-2002 economic collapse.

She had, however, already built a political career on her own terms, winning a legislative seat in the Patagonian province of Santa Cruz in 1991 when her husband became the province's governor. She later represented the remote province in the national senate and chamber of deputies.

Political analysts speculated after her presidential win that the couple planned to alternate four-year terms in the Casa Rosada, the country's presidential palace, thanks to Argentinian laws letting presidents serve unlimited, non-consecutive terms. Argentinian law allows presidents to serve two consecutive terms.

Such speculation ended with her husband's death of a heart attack last October, after which Kirchner has dressed in black. Some Argentinians say she has drawn sympathy and rallied more support by showing she can lead and persevere as a widow.

Kirchner has also been helped by a rising economy that has neutralised the negative impact of rapid inflation.

Since her husband became president in 2003, Argentina's economy has enjoyed strong growth, surging by as much as 9% a year. The only weak year was 2009, when the economy grew just 0.9% amid the global downturn. The government predicts 4.3% growth this year.

Kirchner's supporters also credit her government with helping the poor through benefits, including monthly payments of $50 a child to the unemployed and domestic workers. The money is given on the condition the children are vaccinated and attend school. According to official figures, 4.5 million children benefit from this programme.

To win in the first round, a candidate needs at least 45% of the vote, or 40% if the second-place finisher is at least 10 percentage points behind. If no candidate wins the first round of voting in October, a second round would be held in November. The field of candidates will be finalised in party primaries on 14 August.

Opponents have alleged mismanagement and corruption by Kirchner's government, and have also accused her government of manipulating official statistics. The government, for instance, estimates there will be 8.4% inflation this year while independent analysts say the real inflation rate is likely to be above 25%.

Lawyer Sergio Schoklender, the group's legal representative, is accused along with his brother Pablo and more than a dozen others of fraud, money laundering and illegal enrichment. The authorities' widening investigation has focused on the use of public funds that were intended to go toward the organisation's social projects.

While earning about $16,000 a year in his role, Schoklender amassed a mansion, Ferrari and Porsche sports cars and a yacht, according to the opposition newspaper Clarin.

"The Schoklender case carries significant political damage for the government and will have an electoral cost, although today it's unclear how much and in four months many things can change," said Rosendo Fraga, a political analyst with the New Majority think tank.

Haime, however, said he doubts the scandal poses any real threat to Kirchner.

"There's an electoral climate in which the government seems unbeatable," Haime said.